In the context of this application, the term “battery” is used as a synonym for the entirety of an electrical energy store accommodated in a support frame, and therefore also obviously includes rechargeable batteries and an arrangement of a plurality of individual cells. The term “electric vehicle” includes in particular an electromotively driven passenger car and relates both to fully electrically driven cars and hybrid cars, i.e. ones which have a drive in which, depending on the drive concept and operating state, an electric motor and combustion engine are used jointly or alone to provide the drive energy.
Electric vehicles with a fully electric or at least partially electric or hybrid drive require—depending on the drive concept—the accommodation of batteries with a weight of up to several hundred kilograms. For the accommodation of the batteries in the vehicle, a number of aspects need to be taken into consideration.
The batteries should be arranged in a support structure that is sealed towards the outside, such that any leakage of a battery does not result in liquid escaping from the battery being able to pass into the environment. In terms of production, this demands that the support structure should form an at least downwardly sealed tray which prevents any escape of liquids under gravity in the event of damage (battery housing defect, accident, etc.). In addition, the support structure should be sealed from the outside to the inside, for instance in order to prevent moisture and/or dirt from passing from the outside into the interior of the battery carrier frame, which could in turn increase the risk of short-circuits or other functional impairments.
On account of the size of the batteries of modern electric vehicles, the support structures used for the batteries are increasingly also taking on structural tasks within the vehicle body. Therefore, a construction of a support structure accommodating the battery should take account not only of the forces that arise during driving and the interaction of the support structure with the rest of the body, but also in particular the loads that arise in the event of a crash.
Both of the abovementioned demands mean that the connection of the structural components from which the support structure accommodating the battery is constructed has to be sufficiently leak tight and stable. However, the metal profiles that are preferably used to produce the support structure have—not least on account of employed profile lengths of sometimes much more than one meter—dimensional deviations at the connecting points that are preferably to be joined in a cohesive manner (typically in the corner region of a frame), in particular twists which result in gaps or misalignment of the components to be connected in an order of magnitude, which, in particular in automated welding processes, but also during adhesive bonding operations and other cohesive connecting techniques, can cause problems in terms of strength and tightness of the connection and in process control and automation.
Therefore, it is desirable to provide a support frame for an electric vehicle battery, which is optimized in terms of tightness, compensation of component tolerances and load absorption in particular in the event of a crash, and can be welded readily in an automated manner. It is further desirable to provide a method for producing such a support frame.